Connected: An Internet Encyclopedia
RFC 1072 - 4. TCP ECHO OPTIONS

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### 4. TCP ECHO OPTIONS

A simple method for measuring the RTT of a segment would be: the sender places a timestamp in the segment and the receiver returns that timestamp in the corresponding ACK segment. When the ACK segment arrives at the sender, the difference between the current time and the timestamp is the RTT. To implement this timing method, the receiver must simply reflect or echo selected data (the timestamp) from the sender's segments. This idea is the basis of the "TCP Echo" and "TCP Echo Reply" options.

4.1 TCP Echo and TCP Echo Reply Options
4.2 Using the Echo Options

Next: 4.1 TCP Echo and TCP Echo Reply Options

Connected: An Internet Encyclopedia
RFC 1072 - 4. TCP ECHO OPTIONS